Synergistic Effects of Silicon and Phosphorus Co-Application on Rice (Oryza sativa L.) Growth, Yield and Nutrient Use Efficiency in Saline Soil

Despite the important role of silicon (Si) for the better utilization of plant nutrients, it is not well understood how the combinations of Si and P (phosphorus) will behave as a co-fertilizer for better yield performance and nutrient uptake in saline soil. Hence, the experiment was set-up to assess the effects of different combinations of SixP fertilization on rice (Oryza sativa L.) productivity and nutrient use efficiency in saline soil. Combinedly, three levels of Si (Ca2SiO4: 0, 300 and 600 kg Si ha(- 1)) and four levels of P (TSP: 0, 13.2, 26.4 and 39.6 kg P ha(- 1)) were applied to a salt-tolerant rice (Binadhan-8) variety. Our findings indicate that the SixP combination significantly improved rice growth and yield parameters, except plant height and unfilled grain number. We also found a strong positive correlation between the SixP combination and other essential nutrients (N, P, K and S), implying that the interactive effects of SixP fertilization increased nutrient uptake and NUE. The combination of Si300:P26.4 was identified as the optimum dose, which increased grain yield by 41.66%, straw yield by 55%, N uptake by 216%, P uptake by 193%, K uptake by 263% and S uptake by 130% over control. We conclude that the Si300:P26.4 combination could be an effective dose for improving rice performance and nutrient management in saline soil. The study's limitation is that, despite using Ca-silicate as a source of Si fertilizer, the potential effect of Ca was not considered, which could have an impact on soil P unavailability.